Underwater Vehicles for Navigating Relative to a Structure

The present disclosure relates, generally, to underwater vehicles configured to localise and navigate relative to a structure submerged in a body of water and, particularly, to such vehicles configured for interacting with the underwater structure, particularly to remove fouling from the hull of a vessel.

Various remotely-operable or autonomous vehicles configured for underwater navigation are known. Typically, navigation of the vehicle is enabled by operating drive mechanisms, such as propellers or thrusters, and is guided by processing acoustic sensor signals, such as obtained from a sonar system. This approach to navigation is generally acceptable when navigating through open water, where there are few obstacles with which the vehicle may collide and therefore a wide tolerance for positional accuracy, speed of actuation, and responsiveness is acceptable. However, when operating such systems in close range to fixed or generally immovable structures, such as in a harbour containing boats, or when navigating relative to dynamic structures, such as a boat tethered to a mooring and being moved by currents, the positional accuracy provided by acoustic-based navigation systems can be insufficient to avoid collisions, and generally insufficient to allow the vehicle to interact with the structure.

Some underwater vehicles are equipped with an optical imaging system, typically intended for inspection of underwater structures and/or marine life. Past attempts to navigate based on images obtained from such optical systems alone, or in combination with acoustic signals, have achieved limited success. The low level of light available in underwater environments, potential for turbulence in the water, turbidity of the water, and/or typically few visual features present to image, have resulted in unreliable solutions which have not been commercially adopted.

Structures which are submerged in a body of water, such as a lake, river or ocean, develop fouling over time. Fouling is due to the accumulation of live organisms (biofouling) or non-live substances attaching to surfaces of the structure. If left unattended, fouling degrades the surfaces causing irreversible damage and potentially resulting in mechanical failure of the structure.

Fouling of a vessel's hull is a significant problem as degradation of hull surfaces increase friction between the hull and water. This increases fuel consumed by the vessel during transit, frequency of hull maintenance, and likelihood of mechanical failure of the hull. Proper management of hull fouling involves periodic removal of the fouling (hull cleaning) additionally or alternatively to applying antifouling paint to the hull. Fouling removal often requires removing the vessel from the water, requiring lifting apparatus such as a crane, or a dry dock, to allow manual removal of fouling with tools and/or pressurised water cleaners. Alternatively, vessel hulls are cleaned in-situ by persons diving underwater to manually clean the hull. Both approaches are time consuming, potentially dangerous, restricted by environmental regulation and expensive, particularly where removal of the vessel from the water is required.

Various automated, or semi-automated, systems for cleaning the hulls of vessels, generally intended for cleaning commercial vessels, are known. The majority of such systems are based on a cleaning device ‘crawling’ across the hull to remove fouling, where the device is pressed against the hull, typically by a suction or similar mechanism, or retained on the hull by magnetic wheels, and operated to remove fouling with brushes and/or jets of pressurised water. However, such systems often prove unreliable due to losing contact with the vessel and requiring guidance to restore contact with the hull, some systems even requiring a diver to manually reposition the device on the hull, which is inefficient. Crawling-type systems are also unable to traverse or access particular geometries, such as compound curved surfaces, meaning that the utility of such systems can be limited. Furthermore, the complexity, size and cost of many known systems mean that these are generally impractical and/or cost prohibitive for use by private vessel owners.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims.

Disclosed is an underwater vehicle for navigating relative to a structure submerged in a body of water. The vehicle includes: a body having an operatively front, rear, opposed sides, top and bottom, and defining a peripheral region bounding the front, rear, and opposed sides; one or more drive mechanisms carried by the body; a plurality of imaging modules carried by the body to face away from the peripheral region; and a controller communicatively coupled with the plurality of imaging modules and the one or more drive mechanisms. The plurality of imaging modules are configured to operate concurrently to allow imaging at least partially about at least two of the front, opposed sides, top and bottom of the body. The controller is configured to control operation of the one or more drive mechanisms to navigate the vehicle about the structure based on images captured by the plurality of imaging modules. Navigation may be based on feature recognition in the images, such as by the controller executing one or more image analysis algorithms. The controller may be further configured to control the operation of the one or more drive mechanisms based on the output of one or more other sensors carried by or associate with the vehicle and which are operable to sense a parameter of the vehicle or environment local to the vehicle.

The controller may be configured to determine at least one of a position and orientation of the vehicle relative to the structure based on the images captured by the plurality of imaging modules, and to control operation of the one or more drive mechanisms to navigate the vehicle about the structure based on at least one of the position and orientation of the vehicle relative to the structure.

The imaging modules may be arranged by the body such that a first imaging module faces away from the front portion, and a pair of second imaging modules face away from each of the opposed side portions.

The body may define a notional plane, and at least some of the imaging modules be configured to face at a defined angle transverse to the plane to allow imaging about an operatively top portion or bottom portion of the body at one side of the notional plane.

Each of the first and second imaging modules may be arranged to face at the defined angle to allow concurrent imaging at least partially about the front portion, the opposed side portions, and the top portion. The defined angle of the first imaging module may be different to the defined angle of the second imaging modules.

At least one of the imaging modules may be arranged to face perpendicularly to the notional plane to image about the top portion of the body.

The controller may be configured to control operation of the one or more drive mechanisms to position the notional plane relative to the structure based on the images captured by the imaging modules arranged at the defined angle relative to the notional plane.

The body may carry an interaction module for interacting with the structure, and at least one of the imaging modules may be configured to face at the defined angle to allow imaging adjacent the interaction module, and the controller may be configured to control operation of the one or more drive mechanisms to position the interaction module relative to the structure based on the images captured by the at least some of the imaging modules.

The interaction module may define an elongate structure defining a first end and an opposed second end, and be adjustably mounted to the body to allow positioning the second end to extend past the peripheral region to allow interacting with the structure. In such embodiments, the interaction module may be mounted to the body to allow at least one of displacing the interaction module in a linear direction relative to the body, and rotating the interaction module about at least one axis.

The interaction module may be configured for cleaning the structure, and the interaction module may include at least one rotatable brush at the second end. The interaction module may be releasably mounted on the body to allow replacing with an alternatively configured interaction module, such as configured for inspection, testing, maintenance, or other manipulation of the structure.

The body may carry a pair of the interaction modules to be spaced apart from each other, and at least one of the imaging modules may be arranged between the interaction modules to face perpendicularly to the plane. The at least one imaging module may comprise a pair of stereo cameras.

At least one of the imaging modules may be mounted to the body by an adjustment mechanism operable to adjust the defined angle.

Each of the imaging modules may be operable to define a field of view, and the field of view of at least two of the imaging modules may overlap. The at least two of the imaging modules may be arranged such that the fields of view overlap to allow concurrently imaging at the at least two of the front, opposed sides, top, and bottom of the body.

At least one of the imaging modules may comprise a stereo pair of cameras. The cameras of the stereo pair may be arranged to be angled towards each other.

At least one of the imaging modules may be covered by a domed lens, typically forming a housing over the at least one module. At least one of the imaging modules may be covered by other specific lenses having geometry configured for underwater imaging, such as a wet lens.

The vehicle may also include a plurality of range sensors carried by the body to be spaced from each other, each range sensor operable to determine distance of an object relative to the body, and the controller be communicatively coupled with the range sensors and configured to control operation of the one or more drive mechanisms based on distance data received from the range sensors.

The range sensors may be arranged about the body to face away from the peripheral region and allow measuring distance relative to the front, opposed sides, and/or top of the body.

The body may carry at least one interaction module for interacting with the structure and further include a plurality of range sensors carried by the body to be spaced from each other, each range sensor operable to determine distance of an object relative to the body, and the controller be communicatively coupled with the range sensors and configured to control operation of the one or more drive mechanisms to position the interaction module relative to the structure based on at least one of the images captured by the imaging modules, and distance data received from the range sensors, and further configured to operate the at least one interaction module. In such embodiments, a pair of the interaction modules may be spaced from each other, each interaction module including at least one rotatable brush, and the controller be configured to control operation of each interaction module to rotate the at least one brush based on at least one of the images captured by the imaging modules, and distance data received from the range sensors.

The vehicle may include a plurality of light emitters carried by the body and spaced from the imaging modules, each light emitter operable to illuminate a field of view of at least one imaging module, and the controller be communicatively coupled with the light emitters and configured to control operation of the light emitters.

At least some of the light emitters may be configured as elongate light bars operable to illuminate along a linear length, where at least one light bar is arranged to extend between the opposed sides of the body to illuminate about the top of the body, and a pair of the light bars are spaced from each other to extend along, and illuminate about, the opposed sides of the body.

At least some of the light emitters may be configured as spot lights operable to emit a narrow beam of light, where at least one spotlight is arranged to illuminate about the top of the body, and at least one spot light is arranged to illuminate about the front of the body.

The controller may be configured to control operation of the light emitters based on images captured by the plurality of imaging modules.

The vehicle may include a plurality of range sensors carried by the body to be spaced from each other, each range sensor operable to determine distance of an object relative to the body, and a plurality of light emitters carried by the body and spaced from the imaging modules, each light emitter operable to illuminate a field of view of at least one imaging module, and the controller be communicatively coupled with the range sensors and the light emitters and further configured to control operation of the one or more drive mechanisms based on distance data received from the range sensors, and configured to control operation of the light emitters based on one or more of: images captured by the plurality of imaging modules; distance data received from the range sensors; and estimated position and/or orientation of the vehicle relative to the structure.

The controller may be configured to control operation of the light emitters to adjust one or more of brightness, colour temperature, and strobe frequency of illumination.

The controller may include a processor, or more than one processor, sealably contained within the body. The controller may be configured to effect autonomous navigation relative to the structure.

The vehicle may include a base station mounted outside of the body of water, and a tether connecting the body to the base station. The base station may be mounted at a fixed position relative to the water, or may be carried by a structure floating on the water. The tether may be configured to provide mechanical and/or electrical connection between the body and the base station. The tether may be associated with a drive mechanism operable to adjust the effective length of the tether, such as by winding the tether about a spool, to cause the vehicle to be deployed into, or removed from, the water. The tether may be configured to supply power to one or more batteries arranged onboard the vehicle, and/or communicate data between the vehicle and a server, such as located at the base station, and/or hosted remotely and accessed via the Internet.

Also disclosed is an underwater vehicle configured to clean a structure submerged in a body of water. The vehicle includes: a body defining a peripheral region; and an elongate cleaning module operable to clean the structure, the cleaning module defining a first end and an opposed second end, the cleaning module being adjustably mounted to the body to allow at least one of displacing the cleaning module in a linear direction relative to the body, and rotating the cleaning module about at least one axis, to position the second end to extend past the peripheral region to access the structure.

The cleaning module may define a longitudinal axis between the ends and includes a first brush arranged at the second end and rotatable about the longitudinal axis. The cleaning module may further include a second brush rotatable about the longitudinal axis and spaced axially from the first brush, the first brush and the second brush being rotatable independently of each other.

The body may define a notional plane extending across the peripheral region, and the cleaning module be carried by the body at one side of the plane to be at an operatively top or bottom of the body.

A further cleaning module may be carried by the body at the one side of the plane and spaced from the cleaning module, the further cleaning module defining an axis and having at least one brush rotatably mounted about the axis. The further cleaning module may have a pair of brushes rotatably mounted about the axis and configured to rotate independently of each other.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Applicant's International Patent Application Publication Number WO 2021/026589 describes a system for cleaning a structure arranged in a body of water, the system including a vehicle operable to move through water, a tether connectable between the vehicle and a fixed position, and a deployment mechanism securable relative to the structure and operable to move the vehicle into, our out of, the water, the content which is incorporated herein by reference in its entirety.

10 10 11 10 12 20 25 22 24 34 35 14 20 25 22 24 16 12 10 18 12 14 18 20 22 24 34 35 12 10 26 18 16 26 16 10 18 7 FIG.A In the drawings, reference numeraldesignates an underwater vehiclefor navigating relative to a structure() submerged in a body of water. The vehicleincludes a bodyhaving an operatively front, rear, opposed sides,, topand bottom, and defining a peripheral regionbounding the front, rear, and opposed sides,. One or more drive mechanismsare carried by the body. The vehiclealso includes a plurality of imaging modulescarried by the bodyto face away from the peripheral region. The plurality of imaging modulesare configured to operate concurrently to allow imaging at least partially about at least two of a front, opposed sides,, topand bottomof the body. The vehiclealso includes a controllercommunicatively coupled with the plurality of imaging modulesand the one or more drive mechanisms, the controllerconfigured to control operation of the one or more drive mechanismsto navigate the vehicleabout the structure based on images captured by the plurality of imaging modules.

10 10 10 10 10 10 10 The vehicleis configured to allow precise localisation and navigation relative to a structure defined by, or associated with, a vessel submerged in the body of water, e.g. a boat. In some embodiments, the vehicleis also operable to clean the vessel and associated structures, such as a hull (not shown), keel (not shown), propellers (not shown), chains (not shown), and the like. Typically the vehicleis secured to the vessel, such as by a tether (not illustrated), to allow communicating electrical power from a power supply to the vehicle, as well as retracting the vehicletowards the vessel and lifting the vehicle out of the water, for example, should power be lost or the vehicle not be in use. In some embodiments, the vehicleis secured to part of a dock, such as a jetty (not shown), and is operable to navigate relative to boats in a harbour and/or the jetty. Similarly, the vehiclemay be secured to a static structure, such as an oil rig platform (not illustrated) is operable to navigate relative to the platform, such as to allow inspection and/or conducting maintenance.

1 3 FIGS.to 18 12 18 20 18 22 24 10 18 18 12 22 24 12 a b a b Referring to, the imaging modulesare shown arranged by the bodysuch that a first imaging modulefaces away from the front, and a pair of second imaging modulesface away from each of the opposed sides,. In this embodiment, the first imaging moduleand the pair of second imaging modulesare mounted to the bodyto allow concurrently imaging about opposed sides,of the body.

18 12 10 18 18 12 14 20 22 24 34 35 12 It will be appreciated that the illustrated arrangement of the imaging modulesabout the bodyis exemplary and that the vehicleis alternatively configurable to have more, or less, imaging modules. It will also be appreciated that the modulesmay be alternatively arranged by the bodyto face at least partially away from the peripheral regionand allow concurrent imaging about at least two of the front, opposed sides,, top, and bottomof the body.

18 18 22 24 20 12 18 18 20 22 24 12 a b b b For example, in some embodiments (not illustrated), the first imaging moduleis omitted and the pair of second imaging modulesare each configured to have a field of view (FOV) wide enough to image about one of the opposed sides,and at least partially about the frontof the body. In some embodiments, each of the second imaging modulesdefines a FOV of approximately 180 degrees. In this configuration, the pair of second imaging modulesare operable to image at least partially about the frontand concurrently image each of the opposed sides,of the body.

12 18 18 14 18 14 18 14 34 12 34 18 15 35 12 35 In further embodiments (not illustrated), the bodycarries an annular array of imaging moduleswhere each moduleis arranged to face radially outwards from the peripheral region. For example, some embodiments may include eighteen, or thirty-six, evenly spaced imaging modulesin the annular array to allow concurrent imaging entirely around the peripheral region. In yet other embodiments, some of the modulesin the annular array are directed away from the peripheral regionand partially towards the topof the body, to allow imaging about the top, and other modulesin the array are directed away from the peripheral regionand partially towards the bottomof the body, to allow imaging about the bottom.

10 18 12 18 18 20 22 24 34 12 18 10 35 12 10 c a b c In the illustrated embodiment, a third imaging moduleis carried by the bodyand configured to operate concurrently with the first imaging moduleand the pair of second imaging modulesto allow concurrent imaging about the front, sides,, and the topof the body. It will be appreciated that, in other embodiments, the third imaging modulemay be omitted where imaging operatively above the vehicleis not required, or arranged in, or otherwise facing away from, the bottomof the bodywhere imaging operatively below the vehicleis required.

18 17 18 19 21 18 18 18 18 23 17 23 18 35 10 a c c c Each of the plurality of imaging modulesincludes at least one optical camera, and at least one of the imaging modulesis configurable to include a stereo pair of cameras,, for example, the first imaging moduleand the third imaging module, to assist with resolving the depth of an object in the field of view of the at least one of the imaging modules. The third imaging moduleincludes a third camerafor imaging the surface of the structure from a short distance, for example, to allow visual inspection to identify fouling on the structure, and monitor the progress of fouling removal as the structure is being cleaned. Each camerais typically configured to record images using a conventional visible light-based RGB sensor and may additionally, or alternatively, include an infrared or other light-based sensor. The third camerais typically configured to capture high resolution images or video to allow detailed inspection of structures, such as boat hulls or seabeds, and/or allow photogrammetry reconstructions. It will be appreciated that, in some embodiments (not illustrated), the third imaging modulemay be arranged to face away from the bottomto image operatively under the vehicle.

12 40 20 22 24 18 40 18 18 42 40 10 10 18 18 10 34 12 40 12 36 18 12 18 40 4 5 FIGS.and 4 5 FIGS.and a b The bodydefines a notional (virtual) planebetween the frontand opposed sides,, and at least some of the imaging modulesare configured to face at a defined angle transverse to the plane. This arrangement of the moduleallows operating modulesto image at one sideof the notional plane, being above or below the vehicle. Best shown in, and discussed further below, in the illustrated embodiment, some of the imaging modules,are arranged at the defined angle to image operatively above the vehicle, i.e. adjacent the topof the body. The notional planemay be defined by at least three points of the body, such as defined at the top portion.show the spaced relationship of the plurality of imaging moduleswithout showing the bodyto more clearly illustrate the defined angle of the plurality of imaging moduleswith reference to the plane.

4 FIG. 18 18 40 44 46 18 40 14 12 18 18 40 48 18 18 40 b b b c c Referring to, being a front view schematic of the imaging modules, the defined angle faced by each of the second imaging modulesrelative to the planeis shown by the line of sight,of each of the imaging modulesintersecting the planeat the defined angle, identified as “A”. The defined angle may be any suitable angle greater than 0 and less than 90 degrees, typically being between 30 and 75 degrees to provide a balance of imaging away from the peripheral regionand above the body. It will be understood that the defined angle of each of the pair of second imaging modulesmay be the same or different to each other. The third imaging moduleis arranged to face perpendicularly to the planeas shown by the line of sightof the imaging module, and it will be understood that further imaging modulesmay be included which also face perpendicularly to the plane.

5 FIG. 18 18 40 50 18 40 14 12 18 18 34 12 18 18 40 18 14 40 18 34 12 a a a b b Referring to, being a side view schematic of the imaging modules, the defined angle faced by the first imaging modulerelative to the planeis shown by the line of sightof the imaging moduleintersecting the planeat the defined angle, identified as “B”. The defined angle may be any suitable angle greater than 0 and less than 90 degrees, typically between 10 and 60 degrees to provide a balance of imaging away the peripheral regionand above the body. In this embodiment, the defined angle B faced by the first imaging moduleis less than the defined angle A faced by the pair of second imaging modulesin order to encompass less of the space adjacent the topof the bodyin its field of view compared to the pair of second imaging modules. It will be understood that none of the plurality of imaging modulesmay face at an angle that intersects the plane, that is, all of the plurality of imaging modulesmay face directly away from the peripheral regionin a direction parallel to the plane. In such an embodiment, some or all of the plurality of imaging modulesmay optionally have a sufficiently wide field of view so as to at least partially image the space adjacent the topof the body.

10 18 12 18 12 18 26 18 40 In the illustrated embodiment, each of the plurality of imaging modulesare fixedly mounted to the bodysuch that the defined angle is fixed. In some embodiments (not illustrated), at least one of the imaging modulesis mounted to the bodyby an adjustment mechanism (not shown) operable to adjust the defined angle, for example, by having a lockable ball and socket mount, or having a gimbal-type mount operable to rotate the imaging moduleabout at least one axis. It will be appreciated that the controllermay be communicatively coupled with the adjustment mechanism to allow selectively orientating the imaging modulerelative to the notional plane.

10 52 36 12 52 52 54 56 58 55 56 58 52 56 60 55 58 62 55 60 60 62 26 60 62 54 52 63 55 60 62 63 60 62 The illustrated vehicleincludes an interaction moduleconfigured for interacting with the structure. The top portionof the bodycarries the interaction module, configured as a cleaning module configured for cleaning the structure. The moduledefines an elongate structuredefining a first endand an opposed second end, and a longitudinal axisbetween the ends,. The interaction moduleincludes at least one rotatable brush for cleaning the structure, and in the illustrated embodiment, the first endhas a first brushrotatably mounted about the axisand the second endhas a second brushrotatably mounted about the axisand spaced axially from the first brush. The first and second brushes,are typically rotatable independently of each other via the controller. The brushes,are each mounted to a spindle (not shown) of the elongate structureand each may include comprise bristle or resiliently flexible tabs (not shown). The interaction moduleincludes two further brushesrotatably mounted about the axisand positioned axially along the spindle between the outer brushes,. The brushesare typically configured to rotate together with the adjacent outer brush,.

52 52 60 62 63 52 52 12 52 It will be understood that the interaction moduleis configurable for alternative interactions with the structure, such as gripping, cutting, drilling, probing/measuring with a sensor, or imaging, such as with a 3D scanner. Furthermore, the interaction modulemay be configured for cleaning the structure by polishing, scraping, abrading, sanding, and the like, such as by alternatively configuring the surface texture or bristles of the brushes,,. It will also be understood that the number of brushes may vary in other embodiments, for example, the interaction modulemay include one, two, three, four, or greater than four brushes. Typically, the interaction moduleis releasably engaged with the bodyto readily allow removal and replacement with another, alternative interaction module, such as to allow providing a different function and interaction.

6 6 FIGS.A andB 52 12 56 58 14 12 10 52 64 12 66 52 14 52 52 58 52 52 14 Best shown in, optionally, the interaction moduleis adjustably mounted to the bodyto allow pivoting about an axis adjacent the first (pivot) endto allow pivoting the second (free) endto extend past the peripheral regionof the bodyto allow interacting with the structure. In the illustrated embodiment, the interaction moduleincludes a bracketmounted to an electric motor (not shown) contained in the bodyvia a pin jointwhich allows the interaction moduleto pivot and extend past the peripheral region. This extended or ‘jousting’ configuration of the interaction moduleallows the interaction module, and particularly the free end, to interact with target portions of the submerged structure, or with portions of the structure located above the water line, by urging the interaction moduleinto the target portions. The extended configuration of the interaction modulecan be useful to comprehensively access target portions which include concave, or other complex geometry, structures, or access through apertures or into recesses dimensioned to be less than the peripheral region.

52 12 12 52 12 12 62 14 It will be appreciated that, in other embodiments (not illustrated), the interaction moduleis mounted to allow sliding in one or more linear directions relative to the body, and/or pivoting relative to the bodyabout two, or more, axes. In some embodiments (not illustrated), the moduleis mounted to the bodyby a mechanism configured to pivot about an axis arranged substantially mid-way across the front of the body, and then displace the modulelinearly away from the peripheral region. Such embodiments may be useful to limit force exerted through the pivot axis during use.

18 18 52 18 12 18 18 52 20 34 14 52 18 a a b c a. 1 3 FIGS.to 6 FIG. At least one of the imaging modules, in the illustrated embodiment being the first module, is configured to face at the defined angle to allow imaging adjacent the interaction module. The first imaging moduleis mounted to the bodyat an operatively lower position compared to the second and third imaging modules,in order to include at least a majority of the interaction modulein its field of view, as well as the front, and optionally the top, of the peripheral region. In this way, the interaction modulein both its aligned () and extended () configurations may be monitored by the first imaging module

10 36 12 52 68 68 52 34 12 12 52 28 12 18 52 68 40 18 18 52 68 52 68 c c In the illustrated embodiment, the top portionof the bodycarries a pair of the interaction modules,spaced apart from each other. One of the interaction moduleshas the same features as the other interaction moduleand is carried proximate the rear portionof the bodyby being fixedly mounted to the body, and the other interaction moduleis carried proximate the front portionof the body. At least one of the imaging modulesis arranged between the interaction modules,to face perpendicularly to the plane, which in this embodiment is the third imaging module. The imaging moduleis operable to include both of the interaction modules,and the structure in its field of view in order to image one, or both, of the interaction modules,interacting with the structure.

1 3 6 FIGS.toand 3 FIG. 2 FIG. 16 72 74 72 74 10 72 12 12 12 74 72 74 10 Referring to, the drive mechanismsinclude ducts which house eight thrusters,rotatable by electric motors (not illustrated). The ducts are arranged such that operation of the thrusters,enables moving the vehiclefreely in three-dimensional space through the water, in a swimming-type motion. Four of the ducts position some of the thrustersabout the periphery of the bodyto allow rotation of the bodyabout a yaw axis A () and translate the bodyin a forwards, reverse and sideways direction. The other four ducts position the other thrustersto allow rotation of the body about a pitch axis B and roll axis C () and translate the body along the yaw axis A to adjust depth. The arrangement and operation of the thrusters,allows unrestricted propulsion of the vehiclethrough the water, and can enhance precise control of the vehicle's position and/or orientation relative to a structure, and/or enhance accessing complex geometry structures.

26 16 12 10 26 10 10 18 16 10 10 26 12 10 72 74 10 26 10 12 The controlleris connected to the drive mechanismsto effect translation and/or rotation of the bodyto navigate the vehiclerelative to the structure. In some embodiments, the controlleris configured to estimate or determine at least one of a position and orientation of the vehicle, or determine pose of the vehicle, relative to the structure based on the images captured by the plurality of imaging modules, and to control operation of the one or more drive mechanismsto navigate the vehicleabout the structure based on the determined position and/or orientation of the vehicle. In the illustrated embodiments, the controllerincludes one or more processors (not shown) sealably contained within the bodyand operable to determine position and orientation of the vehiclerelative to the structure, and operate the thrusters,as a result. In other embodiments (not illustrated), the vehicleincludes only a single drive mechanism operable by the controllerto navigate the vehiclethrough the water, for example, a thruster rotatably mounted to the bodyabout two axes.

6 FIG.B 10 FIG. 10 FIG. 12 27 26 12 27 27 26 52 68 18 18 10 12 69 20 12 26 69 12 12 26 Best shown in, the bodydefines, or carries, a sealed containerhousing the controllerand other electronic components. The bodymay also carry a range of sensors within the container, or external to the containerand communicatively coupled to the controller, including any of ultrasonic sensors, a barometer, hall effect sensors, temperature sensors, force and/or current sensors operatively connected to the interaction modules,and/or the tether, and inertial measurement units (IMUs) which may be connected to one or more of the plurality of imaging modulesin order for the plurality of imaging modulesto provide visual inertial odometry for navigating the vehicle. In the illustrated embodiment and best shown in, the bodyalso carries an array of range sensorsarranged at the frontand/or each corner of the body, and communicative coupled with the controller. As described in greater detail below with reference to, the range sensorsare operable to allow determining any of distance of the bodyfrom the submerged structure, orientation of the bodyrelative to the structure, and angle offset of planes. The controlleris configured to communicate with any of these sensors to allow receiving multi-modal sensed information.

10 26 18 10 16 10 26 10 11 26 16 10 18 26 18 The position and orientation of the vehicleis generally estimated or determined by the controllerby calculation based on outputs from the plurality of imaging modules. This may also include incorporating data received from the one or more sensors on board the vehicle, and/or tracking the inputs and outputs of the drive mechanismsand referring to a point in space corresponding to the point from which the vehicleis launched. In some embodiments, the controlleris not configured to determine position, orientation, or pose of the vehiclerelative to the structureor other reference frame, and instead, the controlleris configured to control the drive mechanismsto move the vehiclesuch that a feature of the structure remains within a predetermined pixel size range as captured by the plurality of imaging modules. Such an embodiment of the controllermay employ feature detection from the images captured by the plurality of imaging modules.

26 16 40 18 40 10 40 36 12 16 36 56 68 18 52 18 26 16 52 18 a The controllermay be configured to control operation of one or more of the drive mechanismsto position the notional planerelative to the structure based on the images captured by the imaging modulesarranged to face at the defined transverse angle relative to the notional plane. For example, in the illustrated embodiment, the notional planeis parallel to the top portionof the body, meaning that operating the drive mechanismsin this way allows urging the top portion, and consequently the interaction modules,, towards the submerged structure. In embodiments where at least one of the imaging modulesis configured to face at the defined angle to allow imaging adjacent the interaction module, for example, the first imaging module, the controllermay be configured to control operation of the one or more drive mechanismsto position the interaction modulerelative to the structure based on the images captured by the imaging modulesarranged to face at the defined angle.

10 26 10 11 10 26 10 26 10 26 12 12 18 16 10 It will be understood that the vehiclemay be an unmanned underwater vehicle and the controllerbe configured to effect autonomous localization and navigation of the vehiclerelative to the structure. It will also be understood that the vehiclemay be a semi-autonomous vehicle allowing a user to override the controllerand manually remotely control the vehicle, such as to navigate past an obstacle. In other embodiments, the controllermay not be fully carried by the vehicle, for example, the controllermay be in a master/slave configuration and comprise a primary controller (not shown) located remotely from the body, and a secondary controller sealably contained within the bodyand configured to transmit the images captured by the plurality of imaging modulesto the primary controller. The primary controller may be configured to transmit a command to the secondary controller to control operation of the one or more drive mechanismsto navigate the vehicleabout the structure based on the images received from the secondary controller.

26 10 52 68 18 26 20 10 26 26 The controllermay be operable to determine a fouling or other condition of the structure. This may involve assessing data collected by sensors arranged in or on the vehicle, such as force sensors associated with the interaction modules,, and/or images captured by the plurality of imaging modules. Responsive to determining the fouling condition, the controllermay be configured to adjust a cycle period of the vehicleso that the vehiclecleans the structure sufficiently frequently to prevent fouling being established. The controllermay also include a cycle period timer that defines a time period equivalent to the cycle period minus the duration of the previously executed cleaning schedule (or a default value when first operated). When the timer has elapsed, this causes the controllerto repeat the cleaning schedule by re-initiating the schedule.

26 26 10 18 10 10 10 26 10 In other embodiments, the processing may be performed by a remote server and communicated to the controllervia a wide area network or local area network. In further embodiments, the controllerincludes at least one first processor carried by the vehicle, and at least one second processor located above water, to allow processing by a combination of on-board and off-board (remote) processors. In this way, the processing of the images from the plurality of imaging modulesis not entirely implemented on-board the vehicle, which can limit computational power required to to be provided by the vehicleitself. This can decrease the energy cost and weight of the vehicle, and, as a result, enhance electrical and kinematic efficiency. Generally, image processing is performed by a processor of the controllercarried on-board the vehicleto limit latency, which can enhance navigational accuracy and/or responsiveness.

26 12 10 12 12 10 10 a marina In other embodiments, the controlleris not carried by the bodyand instead is located above water, for example, within a base station, such as a garage (not shown), mounted outside of the body of water that is configured to house the vehiclewhen not in use. The base station may be fixedly mounted relative to the water, such as toor other structure adjacent the water, or be mounted to a structure floating on the water, such as a boat or pontoon. In such embodiments, a tether (not shown) may be provided connecting the bodyto the base station. The tether is configured to provide mechanical connection, and may also provide electrical connection, between the bodyand the base station. The tether allows a drive mechanism to adjust the effective length of the tether, for example, to cause withdrawing the vehicle from the water for storage or maintenance. The tether typically connects the vehicleto a power supply and is configurable to also communicate data between the vehicle and the base station, or a remote server such as accessed via the Internet. In some embodiments, the vehicleis battery powered and require no such tether for mechanical or electrical connection to the base station.

26 10 10 10 26 10 26 10 10 The controllermay be communicatively connected to a deployment mechanism (not shown) via wired or wireless connection, which is configured to deploy the vehiclefrom the base station, such as by unwinding a tether connected to the vehiclefrom a spool, or by lowering a platform supporting the vehicleinto the water. The controllermay be configured to cause operation of the vehicleand the deployment mechanism according to a predetermined cleaning schedule which is may be user-modified or generated by the controllerbased on a geometry of the structure submerged in water. The deployment mechanism may be operable to deploy and recover the vehiclefrom the water by adjusting an effective length of the tether. The deployment mechanism may also operate to reduce slack in the tether whilst the vehicleis moving through the water around the structure.

26 10 10 10 26 10 10 In other embodiments, the controllermay be operatively connected to a communications module, typically being a wireless cellular network module, to allow communicating with a remote server via the Internet. Communicating with the remote server may allow, for example, uploading data captured by the vehicleto enable monitoring of the vehicleand/or analysis of the data, downloading software updates, operational instructions, and the like, and enables remote control of the vehicleby a user, for example, to effect maintenance or resolve an error. Based on information from the remote server, the controllermay be configured to determine environmental conditions such as local water turbulence conditions, prevailing currents, wave height, and adjust the cycle period so that the vehicleis deployed at appropriate times to avoid damage to the vehicleand the structure.

12 12 10 90 12 20 12 90 34 12 12 22 24 35 12 18 10 11 FIG. The bodyis dimensioned to be small-scale and sufficiently lightweight to be man-portable. A handle (not shown) may be defined at one side of the bodyto assist manual transport of the vehiclewhen out of the water. Lighting elements, such as shown inand discussed in greater detail below, may also be secured to the body, for example, one or more first lighting elements may be arranged to illuminate adjacent the frontof the bodyand one or more second lighting elementsmay be arranged to illuminate adjacent the topof the body. It will be appreciated that, in other embodiments (not shown), further lighting elements may be carried by the bodyto illuminate about the sides,, and/or bottomof the body, for example, to enhance the quality of images captured by the imaging modules, which consequently can enhance precision of control of the vehicle.

76 78 80 82 18 7 9 FIGS.A-B The fields of view,,,defined by the plurality of imaging modulesare configurable in a number of different ways. These are discussed below with reference to.

7 7 FIGS.A andB 76 78 80 82 18 10 10 11 11 76 78 80 82 show schematic perspective and top views, respectively, of a first configuration of the fields of view,,,of the plurality of imaging modules, where each field of view is shown as frustum extending away from the vehicle. In these figures, the vehicleis located approximately 500 mm from the structuresubmerged in water, the structurerepresenting a double-curved portion of a hull of a boat, and the intersection of each field of view,,,is illustrated.

7 FIG.A 76 78 80 82 18 20 22 24 34 12 18 76 78 80 82 26 76 78 80 82 Best shown in, the fields of view,,,of the plurality of imaging modulesare directed to allow concurrent imaging of a space adjacent the front, the opposed sides,, and the topof the body. The imaging modulesare arranged and configured so that the fields of view,,,do not overlap in this configuration, meaning the controllerappends the fields of view,,,together to form a combined field of view.

8 8 FIGS.A andB 8 8 FIGS.A andB 76 78 80 18 10 10 11 11 76 78 80 82 82 18 c show schematic perspective and top views, respectively, of a second configuration of the fields of view,,of the plurality of imaging modules, where each field of view is shown as frustum extending away from the vehicle. In these figures, the vehicleis located approximately 500 mm from the structuresubmerged in water, the structurerepresenting a double-curved portion of a hull of a boat, and the intersection of each field of view,,,with the hull is illustrated. The field of viewof the third imaging moduleis not shown in.

8 FIG.A 76 78 80 82 18 20 22 24 34 12 18 76 78 80 19 21 18 76 76 19 21 19 21 19 21 76 76 18 20 14 a a b a b b Best shown in, the fields of view,,,of the plurality of imaging modulesare directed to allow concurrent imaging of a space adjacent the front, the opposed sides,, and the topof the body. The imaging modulesare arranged and configured so that the fields of view,,are directed to overlap. This also involves the stereo pair of cameras,of the first imaging modulebeing arranged to be angled towards each other so that the fields of view,of each of the stereo cameras,overlap. In other embodiments, only one of the stereo cameras,may be angled towards the other camera,in order for their fields of view,to overlap. To enhance the extent of overlap, the second imaging modulesare arranged to be slightly directed towards the frontof the peripheral region.

20 22 24 12 26 76 78 80 76 78 80 76 78 80 82 20 22 24 12 76 78 80 18 10 10 In this configuration, imaging about at least the frontand opposed sides,of the bodyrequires the controllerto register and/or align, and/or stitch together, two or more of the fields of view,,to form a combined field of view. The stitching together of the fields of view,,is more computationally intensive than appending the fields of view,,,as required by the first configuration. However, the stitching together can allow forming a continuous or seamless combined field of view which can enhance imaging about the frontand opposed sides,of the body. This combined field of view from the overlapping fields of view,,may also allow for an object to be imaged by more than one of the plurality of imaging modulessimultaneously, which may assist in resolving the depth of the object from the vehicle, or otherwise enhance accuracy of positioning the vehiclerelative to the object.

18 76 78 80 76 78 80 82 18 76 78 80 10 18 12 18 76 78 80 82 18 c It will be understood that the imaging modulesare configurable so that only some, not all, of the fields of view,,overlap. For example, in some configurations only two of the fields of view,,overlap, and in other configurations, the field of viewof the third imaging moduleoverlaps with one or more of the other fields of view,,. It will also be understood that in embodiments of the vehiclewhere the imaging modulesare mounted to the bodyby an adjustment mechanism, the adjustment mechanism may be operable to adjust the defined angle faced by the plurality of imaging modulesand thereby alter the configuration of one or more of the fields of view,,,to alter the plurality of imaging modulesbetween the first (spaced) and second (overlapped) configuration.

18 18 84 18 18 In some embodiments, each imaging moduleis covered by a flat (planar) port, and in other embodiments, at least one of the imaging modulesis covered by a domed port. In either arrangement, the port is typically formed from a transparent material to act as a lens to affect images captured by the imaging modules. Each port typically forms a housing over the associated imaging module.

9 FIG.A 9 FIG.B 9 FIG.B 9 FIG.A 10 76 78 80 18 18 10 76 78 80 18 18 84 76 78 80 76 78 80 18 a b a b shows a schematic top view of the vehicleillustrating the fields of view,,where the first and second imaging modules,are covered by the planar port.shows a schematic top view of the vehicleillustrating the fields of view,,where the first and second imaging modules,are covered by a domed port. As shown in these figures, the configuration of the port can affect the extent (volume) of the fields of view,,, where the fields of view,,cover a larger volume in the configuration ofcompared to. It will be appreciated that broadening the field of view can be achieved by alternative means, such as configuring each moduleto include a specific lens.

10 FIG. 69 12 12 26 69 16 72 74 69 10 11 26 16 18 26 10 illustrates positioning of a plurality of range sensorsspaced across the bodyto allow measuring distance to a complementary plurality of points spaced from the body. The controlleris communicatively coupled with each of the range sensorsand typically configured to control operation of the drive mechanisms, in this embodiment being the thrusters,, based on distance data received from the range sensors, such as to effect navigation of the vehiclerelative to the structure. The controlleris typically configured to control the drive mechanismsbased on the distance data in combination with analysis of the images captured by the imaging moduleshowever it will be appreciated that the controllermay select between, or both, of these sources to guide navigation of the vehicle, for example, depending on the local environmental conditions.

10 12 69 14 20 22 24 25 22 24 12 69 40 69 34 12 69 20 22 24 34 12 69 34 12 52 60 62 34 69 34 69 12 12 69 69 10 FIG. In the illustrated embodiment, the bodycarries a first array of the range sensorsarranged about the peripheral regionat each corner between frontand side,, and between rearand side,of the body. The range sensorsof the first array may be directed at a transverse angle relative to the notional plane, such as shown inwhere these range sensorsare partially directed towards the topof the body. Operating these range sensorsallows measuring distance relative to the front, opposed sides,, and topof the body. The bodyalso carries a second array of range sensorsspaced across the topof the body, in this embodiment, being between the interaction modulescarrying the brushes,to face directly away from the top. Operating these range sensorsallows measuring distance relative to the topof the body. It will be appreciated that the illustrated arrangement of the range sensorson the bodyis exemplary and that other arrangements are possible, and may be useful, and that the bodymay carry more, or less, sensors. The range sensorsare generally configured as infrared time-of-flight sensors however it will be appreciated that other range or distance sensors may be appropriate.

69 69 12 52 11 69 10 11 11 60 62 69 11 10 11 26 16 52 60 62 8 8 FIGS.A andB The arrangement of the range sensorsin the first array can usefully position the range sensorsat the extents of the bodyand outside of the interaction modulesto have uninterrupted line of sight to an adjacent object, such as the hullof a vessel, as shown in. Operating the range sensorsof the first array measures distance to an adjacent object. When the vehicleis driven to be adjacent the structure, such as to clean the structurewith the brushes,, operating the first array of range sensorscan measure relative distance to a surface or edge of the structurein front of and behind the vehicle, and can also detect the absence of the structure, such as due to travelling past an edge. Distance data generated by these measurements is processed by the controllerto effect adjusting control of the drive mechanismsand/or adjusting control of the interaction modules, such as to enhance effectiveness and/or efficiency of cleaning the structure by rotating the brushes,.

69 69 52 11 52 60 62 11 69 34 12 69 10 11 10 FIG. The arrangement of the range sensorsin the second array can usefully position the range sensorsinboard of the interaction modulesto measure relative distance to a surface of the structureadjacent, or touching, the modules, such as during a cleaning operation when operating the brushes,pressed against the structure. As shown in, the sensorsmay be positioned in a grid at four corners of the top portionof the body. The distance data generated by these sensorsallows the controller to monitor spacing of the vehiclefrom the structure.

69 26 11 11 69 34 10 16 52 52 69 26 The range sensorsmay be arranged and operable so that distance data derived from one or both of the arrays allows the controllerto determine, or estimate, the geometry of an adjacent object, such as the structure, for example, to identify a boundary and/or shape of the structure. For example, operating the sensorsin the second array may allow determining, or estimating, a profile of a surface adjacent the topof the vehicleand, as a result, control operation of the drive mechanismsand/or interaction modulesto optimise force applied by the interaction modulesto the surface. In some embodiments, the second array may include more sensorsto enhance resolution of the surface geometry estimation achievable by the controller.

26 69 69 60 62 116 52 11 52 26 116 52 72 74 60 62 60 62 52 The controllermay be configured to combine (or fuse) the distance data generated by the sensorsin the second array with the distance data generated by the sensorsof the first array, and may be combined with other sensor data, such as force data generated from force sensors associated with the brushes,, to further enhance accuracy and/or efficiency of control of the drive mechanismsand/or interaction modules. This can enhance navigational precision about the structure, for example, to effect cleaning or other tasks performed with the interaction modules. It will be appreciated that data obtained from other sensors may be combined/fused with the distance data, by the controller, to optimise control of the drive mechanismsand/or interaction modules. For example, this may involve obtaining and combining any of electrical current and/or rotational speed measurements from sensors associated with the thrusters,, electrical current and/or rotational speed measurements from sensors associated with the brushes,(or motors driving the brushes,), and inertial measurement units (IMUs) associated with the interaction modules.

11 FIG. 90 12 18 90 18 90 18 18 26 90 90 90 90 90 illustrates positioning of a plurality of light emittersspaced across the bodyand from the imaging modules. Each light emitteris operable to illuminate a field of view of at least one of the imaging modules. Generally, each light emitteris spaced away from the imaging modules, and may be angled toward the field of view of one or more modules, to inhibit emitted light from illuminating immediately in front of the module, such as to avoid illuminating particles or bubbles prominently located in the field of view. The controlleris communicatively coupled with each of the light emittersand configured to control operation of the light emitters, such as to activate/deactivate one or more of the light emitters, and adjust any of brightness, colour temperature and strobe frequency of illumination caused by each light emitter. Generally, each light emitterincludes one or more light emitting diodes (LEDs) however it will be appreciated that other illumination mechanisms are suitable.

10 90 92 94 92 10 92 10 92 18 26 11 94 10 In the illustrated embodiment, some of the light emittersare configured as elongate light bars, and other light emitters are configured as spot lights. Operating the light barsilluminates along a linear length. In practice, this emits a diffuse light or glow across a short range, typically employed for illuminating an object less than 100 mm away from the vehicle. In some circumstances, the light barsmay be operated to increase the emitted brightness to illuminate objects around 200 mm away from the vehicle, or greater than 200 mm for some applications. The diffused light emitted by the light barscan usefully minimise reflections from particles, debris, and/or bubbles in the water and, consequently, enhance image quality captured by the imaging modules, which can enhance close range feature recognition and resulting navigational control by the controller, such as when moving about the structure. Operating the spot lightsilluminates a narrow beam across a longer range, typically employed for illuminating objects more than 50 mm away from the vehicle, which can enhance long range feature detection, such as when moving through open water or inspecting concave structures, recesses, or conduits, such as bow thrusters, or other complex geometries.

92 12 18 921 22 24 34 12 34 921 20 25 12 18 921 921 18 10 921 52 52 11 60 62 c c The light barsare arranged to extend across the bodyto emit light in a distributed, short range glow substantially across the fields of view of some of the imaging modules. In the illustrated embodiment, a pair of first light barsare arranged to extend parallel to each other between the sides,at the topof the bodyto illuminate about the top. The first light barsare spaced apart towards the frontand rearof the bodyso that the third imaging moduleis interposed between the light barssuch that operating the light barsilluminates objects within the field of view of the third imaging moduleand close to the vehicle. These light barsmay also be positioned between, and close to, the interaction modulesto enhance illuminating a structure being interacted with by the modules, such as the structurebeing cleaned by the brushes,.

922 22 24 12 22 24 922 12 96 18 921 18 10 b b A pair of second light barsare arranged to extend parallel to, and spaced apart from, each other along the sides,of the bodyto illuminate about the sides,. The second light barsare mounted to the body, in this embodiment to pontoon members, to be operatively below one of the second imaging modulessuch that operating the light barsilluminates objects within the field of view of the second imaging modulesand close to the vehicle.

922 18 26 b Operating the second light barsemits light across the field of view of the module, which can optimise image quality and, as a result, feature recognition by the controller.

94 12 18 941 34 12 34 941 34 18 11 10 60 62 11 c The spot lightsare mounted to the bodyto emit light in a focused, medium to long range beam substantially along the fields of view of some of the imaging modules. In the illustrated embodiment, an array of first spot lightsare mounted across the topof the bodyto illuminate about the top. Operating these spot lightsemits a plurality of beams of light directly away from the topto illuminate objects within the field of view of the third imaging moduleand distantly from the vehicle, for example, illuminating the structureas the vehicleis approaching to urge the brushes,against the structurefor cleaning.

942 20 12 96 18 11 10 11 a A pair of second spot lightsare mounted at the frontof the body, in this embodiment being carried by the pontoon members, to illuminate objects within the field of view of the first imaging moduleand distantly from the vehicle, for example, illuminating the structureas the vehicleis travelling towards the structurefrom a distant location.

26 92 92 10 26 92 18 69 10 11 The controlleris configured to operate any of the light emitters, including operating multiple light emitterssimultaneously, to illuminate around the vehicle. The controllermay be configured to operate the light emittersbased on one or more of: images captured by the plurality of imaging modules; distance data received from the range sensors; and estimated position and/or orientation of the vehiclerelative to the structure.

26 92 10 10 11 10 10 10 92 11 92 18 11 In some embodiments, the controlleris configured to dynamically adjust operation of the light emitters(known as ‘active lighting’) as the vehiclemoves through the water based on any of a range of factors. The dynamic adjustment may be based on one or more of: the estimated or determined relative position and/or orientation of the vehicleand the structure; the location of the vehiclein the world; ambient light local to the vehicle; reflected light local to the vehicle, such as light emitted by the light emittersand being reflected by the structure. Operating the light emittersin this way can mitigate the potentially negative impact on image quality captured by the image modulescaused by the high dynamic range variability of light when illuminating the structurein close proximity underwater.

26 69 92 10 10 11 18 26 For example, in some embodiments, the controllerassesses the distance data generated by the range sensorsat a defined frequency and, as a result, adjusts the brightness output of the light emittersbased on the measured proximity of the vehicle, or a portion of the vehicle, to the structure. This can usefully enhance colour and/or clarity of the images captured by the imaging modules, and/or inhibit creating ‘hotspots’ of light in the images, any of which can enhance feature detection in the images by the controller.

26 18 92 In other embodiments, the controllerassesses the images captured by the image modulesand, as a result, adjusts the brightness output of the light emittersbased on quantity and quality of features detected in the images, such as by assessing shadows and highlights present in the image.

26 18 10 92 In further embodiments, the controllerassesses the images captured by the image modulesin combination with estimated position data/location data, and/or operating condition data for the vehicle, compares current data to historical data and, as a result, adjusts the brightness output of the light emittersbased on previous visits to the same or similar position/location, and/or based on previous experiences of the same or similar situation.

10 10 10 10 18 20 22 24 12 26 26 16 10 11 12 18 In use, the vehiclemay be deployed from and retrieved to a base station, such as a pod or garage secured outside of the water, for example, on a boat or pontoon. The vehiclemay be mechanically tethered to the base station, such as for providing power to the vehicle. When the vehicleis underwater, the imaging modulesare operated concurrently to image about the frontand the opposed sides,of the body. The images are received and processed by the controller. Based on the processed images, and in some embodiments also based on additional sensed parameters, the controllereffects control of the drive mechanismsto navigate the vehiclerelative to the structure, typically to avoid colliding the body, imaging modulesand drive mechanism(s) with the structure.

10 11 11 26 16 10 52 68 11 52 68 11 The illustrated embodiment of the vehicleis operable to interact with the structure, such as to clean the structure. This involves the controllereffecting control of the drive mechanismsto navigate the vehicleto arrange the interaction modules,relative to the structure, and operating the interaction modules,, in this embodiment causing cleaning of the structure.

60 62 11 52 58 11 60 10 18 26 Navigation in this scenario may include urging one or more of the rotating brushes,into the structure, and/or pivoting the interaction moduleinto the extended configuration and urging the free endagainst target portions of the structure, such as concave regions, or regions above the water line. When cleaning above the water line, typically only the second, outer brushis rotated to inhibit water disturbance proximal to the vehiclewhich can otherwise negatively affect image quality captured by the image modules, such as by creating air bubbles or turbulence, and hence interfere with the controllermaintaining navigational accuracy.

18 20 22 34 35 12 10 22 14 24 18 76 78 80 18 18 10 18 76 78 80 18 26 16 10 Advantageously, the plurality of imaging modulesimaging about at least two of the front, opposed sides, top, and bottomof the bodycan enhance the view horizon about the vehicle, such as defining a wide horizon ranging from one sideof the peripheral regionthrough to the other side. The arrangement of the imaging modulesmeans that features are visible within the fields of view,,of the imaging modulesfor prolonged periods of time, and/or may be imaged multiple times, and/or simultaneously by different imaging modules, to enhance perception of the environment surrounding the vehicle. The wide view horizon provided by the imaging modulescan enhance sensor time of obstacles that may come into the field of view,,of the plurality of imaging modules, for example, portions of the structure submerged in water such as propellers of the vehicle, or marine life, which allows more time for the controllerto identify obstacles and actuate the drive mechanismsto move the vehicleaway from the obstacles.

18 10 10 The plurality of imaging modulesare arranged to capture images in order to provide an accurate localisation of the vehicle, typically accurate to within 10 mm, in order to allow the vehicleto navigate precisely relative to the structure.

20 22 24 34 35 12 10 Localisation is achieved by processing images defining the combined field of view of the concurrently operated plurality of imaging modules about two or more of the front, sides,, top, and bottomof the body. Localisation may also involve incorporating data derived form additional on-board sensor inputs generated by any of the range of additional sensors which may be carried by the vehicle, as described above.

10 12 36 11 11 18 40 12 34 12 Where the vehicleis required to navigate one side of the body, such as the top, close to the structure, such as to allow interaction with the structure, localisation may be enhanced by at least some of the plurality of imaging modulesfacing transverse to the notional planedefined by the bodyto at least partly image about the topof the body, and can be further enhanced by employing stereo cameras to resolve depth.

10 10 52 68 10 52 12 10 10 In the illustrated embodiment of the vehicleconfigured to clean the structure, the vehiclemust navigate near to the structure for the interaction modules,to be urged against the structure and operated to clean it. In this scenario, accurate localisation is advantageous to protect the vehicleand the structure from being inadvertently damaged during the cleaning process, and to enhance effectiveness of cleaning. The arrangement of the interaction modulerelative to the bodymay be adjusted between the aligned configuration and the extended configuration, which can enhance protection of the vehicleduring a cleaning process by allowing the vehicleto clean the structure from a safe distance, as well as allowing access to concave or hollow structures, such as inside pipes.

18 76 78 80 22 24 20 12 26 16 10 In embodiments where the imaging modulesare configured such that the fields of view,,overlap, the view horizon can be continuous and is provided from one sidethrough to the other side, and includes the region at the frontof the body. This allows for increased obstacle awareness as the combined field of view that is stitched together may eliminate blind spots and/or further enhance sensing time, to optimise time available for the controllerto control the drive mechanismsto navigate the vehicleaway from obstacles or about the structure.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.